Risk of magnetic storm hitting Earth on September 25

Earth could experience a magnetic storm on September 25 as the Sun releases a giant jet of plasma.

On September 22, a sunspot named AR3835 suddenly erupted, releasing a large amount of plasma into space.

This phenomenon occurs right around the time of the Earth's autumnal equinox, an astronomical phenomenon that only occurs twice a year when the Earth's rotational axis aligns with its orbit around the Sun.

This has increased the likelihood of a magnetic storm, a phenomenon that could have a major impact on our planet in the coming days.

According to space scientists, a coronal mass ejection (CME) was recorded at 21:39 UTC (4:30 a.m. September 23, Hanoi time) when the sunspot AR3835, which was very stable and showed no signs of strong activity before, suddenly emitted an M-class solar storm.

This was an event that scientists did not predict, because AR3835 was thought to lack enough energy to explode.

Currently, this plasma stream is rushing towards Earth at a speed of more than 1,046,073 km/h.

Although NASA models show that most of the plasma will not hit Earth directly and will only slightly affect the magnetosphere, the layer that protects the planet from solar radiation, the timing of the event, close to the autumnal equinox, could increase the risk of a magnetic storm on September 25.

Magnetic storms and potential impacts

Magnetic storms can disrupt radio communications, affect power grids, and even lead to widespread power outages.

At high latitudes, magnetic storms can also produce stunning light displays known as auroras.

The NOAA Space Weather Prediction Center classifies magnetic storms on a scale from G1 to G5, with G5 being the most powerful and capable of causing complete disruption of power and communications systems.

Weaker magnetic storms, such as G1 or G2, which could occur on September 25, are only likely to have minor impacts on infrastructure in areas near the Earth's North or South Poles.

Why is the timing of the autumnal equinox important?

The autumnal equinox is a special time when both hemispheres of the Earth receive equal amounts of daylight and nighttime light, because the Earth's axis of rotation is not tilted to one side or the other in its orbit around the Sun.

The 2024 autumnal equinox falls on the morning of September 22, marking the first day of autumn in the Northern Hemisphere and the first day of spring in the Southern Hemisphere.

Scientific studies have shown that the frequency of magnetic storms increases significantly during the period near the autumnal and vernal equinoxes each year.

The main reason for this increase has to do with the way Earth's magnetosphere, the protective layer against charged particles from the Sun, interacts with the Sun's magnetic field during this time period.

At other times of the year, Earth's magnetic field and the Sun's magnetic field are often not perfectly aligned, which helps Earth avoid much of the impact from charged particle eruptions such as CMEs or solar winds.

However, around the equinoxes, these two magnetic fields align, reducing their ability to "knock out" charged particles and making the Earth more susceptible to magnetic storms.

This phenomenon is called the Russell-McPherron effect, named after two scientists who proposed the hypothesis in 1973 to explain seasonal variations in the frequency of magnetic storms.

Data collected from 1932 to 2014 shows that magnetic storms are twice as likely to occur around the equinoxes than at other times of the year, especially during the months of the summer and winter solstices, when Earth's poles point directly toward or away from the Sun.